Kooltherm K8 Cavity Board

Product Code


Rigid Cavity Wall Insulation

Kingspan Kooltherm K8 Cavity Board is a high performance, fibre-free rigid insulation suitable for cavity wall applications. It has a thermoset phenolic insulation core, sandwiched between two layers of reflective, low emissivity composite foil autohesively bonded to the insulation core during manufacture. This reflective, low emissivity surface improves the thermal resistance of any cavity adjacent to the board.

  • Made in Australia
  • Clear cavity is maintained
  • CodeMark-certified for NCC compliance
  • CFCs/HCFCs free, zero Ozone Depleting Potential (ODP), and low Global Warming Potential (GWP)

Product Data
Declared Thermal Conductivity (λ-Value) 0.023 W/m.K at 23oC
(insulant thickness 25 – 44 mm)
Emittance (Foil Face) E0.06
Product Dimensions 1200 mm x 514 mm (0.61 m2)
Other dimensions available upon enquiry. Minimum order quantities apply.
Nominal Product Thickness 25, 40 mm
Other thicknesses available upon enquiry. Minimum order quantities apply.

Assumption and Key

NCC 2019 prescribes different methods to determine Total R-value Calculations for Volume 1 and Volume 2.

The R-values shown are Total R-values for the building element as required by the Energy Provisions of the National Construction Code, calculated in accordance with AS/NZS 4859.2 2018.

Kingspan Kooltherm® products are manufactured, tested and packaged in conformance with AS/NZS 4859.1:2018.

Examples shown are suitable for NCC Class 1 & 10a housing and Fire-Resisting Construction Type C walls in NCC Class 2 – 9 buildings. For Fire-Resisting Construction Type A & B walls in NCC Class 2 – 9 buildings a Performance Solution is required. Please contact Kingspan Insulation Technical Services on 1300 247 235 or email technical@kingspaninsulation.com.au for further guidance.

Product R-values

Nominal Product Thickness Declared Product R-value
25 mm R1.10
40 mm R1.75

Double Brick Cavity Wall

System R-value

Insulation Thickness Heat Flow In Heat Flow Out
25 mm RT2.2 RT2.3
40 mm RT2.9 RT2.9

Brick / Block Cavity Wall

System R-value

Insulation Thickness Heat Flow In Heat Flow Out
25 mm RT2.2 RT2.2
40 mm RT2.8 RT2.9

Specification Clause

The cavity wall insulation shall be CodeMark-certified Kingspan Kooltherm K8 Cavity Board        mm thick, with a tested smoke obscuration of not more than 100 m2/kg, comprising a CFC/HCFC–free and zero Ozone Depletion Potential (ODP) rigid thermoset phenolic insulation core faced on both sides with reflective, low emissivity composite foil manufactured under a management system certified to BS/I.S. EN ISO 9001:2008, BS/I.S. EN ISO 14001:2004 and BS/I.S. OHSAS 18001:2007 by Kingspan Insulation Pty Ltd and shall be installed in accordance with the instructions issued by them. A Project Specific Warranty provided by Kingspan Insulation must be submitted.

Specify with:

Handling & Storage

The packaging of Kingspan Kooltherm should not be considered adequate for outdoor protection. Boards should be stored inside a building. If, however, temporary outdoor storage cannot be avoided then the boards should be stacked flat on a level base, clear of the ground, and completely protected from inclement weather through use of a polythene sheet or weatherproof tarpaulin. Boards that have been allowed to get wet should not be used.

Resistance to Solvents
The insulation core is resistant to short-term contact with petrol and with most dilute acids, alkalis and mineral oils. However, it is recommended that any spills be cleaned off fully before the boards are installed. Ensure that safe methods of cleaning are used, as recommended by suppliers of the spilt liquid. The insulation core is not resistant to some solvent-based adhesive systems, particularly those containing methyl ethyl ketone. Adhesives containing such solvents should not be used in association with this product. Damaged boards or boards that have been in contact with harsh solvents or acids should not be used.

Kingspan Insulation products are chemically inert and safe to use. A Product Safety Information Sheet is available from Kingspan Insulation Pty Ltd.

Please note that the reflective surfaces on this product are designed to enhance their thermal performance. As such, the will reflect light as well as heat, including ultraviolet light. Therefore, if these boards are being installed during bright or sunny weather, it is advisable to wear UV protective sunglasses or goggles and if the skin is exposed for a significant period of time, protect bare skin with a UV block sun cream.

Foil facings are conductive to electricity – avoid contact with un-insulated electrical cables and fittings.

Installation must be in accordance with AS 3999 Bulk Thermal Insulation Installation and AS 3000 Electrical Installations (Wiring Rules).


Cutting should be carried out either by using a fine toothed saw, or by scoring with a sharp knife, snapping the board over a straight edge and then cutting the facing on the other side. Ensure accurate trimming to achieve close-butting joints and continuity of insulation.

Cavity Wall

Installation should be in accordance with AS 3999:2015, Section 4 – Safety Requirements for Insulation Installation.

1. Construct the inner leaf to at least an appropriate level to allow installation of Kingspan Kooltherm® K8 Cavity Board to proceed.

2. Remove excess mortar and mortar droppings from exposed edges of any installed insulation boards.

3. Offer the Kingspan Kooltherm® K8 Cavity Board to the external face of the internal leaf and secure in place with a retaining disc/clip on each wall tie. Wall tie structure and positioning must be in accordance with the requirements of the NCC.

4. Ensure that each board is firmly abutted with adjacent boards and penetrations so that there are no gaps in the insulation layer.

5. Leave 100mm clearance around any heat producing electrical fittings and 50mm clearance around hot flues (refer to relevant manufacturers instructions).

6. The outer leaf is then built up to the level of the top of the boards and the process is repeated.

7. Ensure that a residual cavity of at least 40 mm is maintained in accordance with the moisture penetration provisions set out in the masonry structures standard AS 3700 as called up in the NCC Volume 1, Section B1.4

Download Brochure (PDF) Download
Pricing and Where to Buy Download
Request Technical Support Download
Project Specific Warranty Download
CAD PDF – Double Brick Cavity Wall_Kooltherm K8 Download
CAD DWG – Double Brick Cavity Wall_Kooltherm K8 Download
BIM 2016 – Kooltherm K8 Cavity Board Download
BIM 2017 – Kooltherm K8 Cavity Board Download
BIM 2018 – Kooltherm K8 Cavity Board Download
BIM 2019 – Kooltherm K8 Cavity Board Download
PSI – Kooltherm Range Download

Management Standards

Standard Management System
ISO 9001:2015 Quality Management
ISO 14001:2015 Environmental Management
ISO 45001:2018 Health and Safety Management
ISO 50001:2011 Energy Management

Product Testing

Characteristic Standard Result
Compressive Stress AS 2498.3 Typically exceeds 100 kPa at 10% compression
Water Vapour Resistance BS EN 12086:1997 / I.S. EN 12086:1998 > 35 MN·s/g

Fire Performance

Test Test Method Result
Flame Spread
Heat Release
Smoke Release
AS 1530.3 Spread of Flame
Index: 0
Development ≤ 3

Environmental Data Table

Aspect Characteristic
Recyclability Non-contaminated insulation site waste is recyclable, but there are currently no facilities in Australia to process returned material
Re-usability Re-usable if removed with care (long term of service expected)
Water Use No water used in Kingspan Insulation’s manufacturing process
Blowing Agent Global Warming Potential (GWP) Manufactured with a blowing agent that has low GWP
Blowing Agent Ozone Depletion Potential (ODP) Manufactured with a CFC/HCFC-free blowing agent that has zero ODP
Packaging Contains 0% recycled product
Polythene wrap and EPS skids 100% recyclable